leaky bulkhead question

[trilinearmipmap]

First off I would buy a spare bulkhead so if anything happens during the replacement you will be OK.

What happens is if the bulkhead gets loose, then some sand/dirt inside the overflow will get between the o-ring and the glass, so the seal not intact.

You need to remove the bulkhead, then clear the glass inside the overflow around the hole for the bulkhead. Also clean the o-ring.

You don't need to use tools, hand-tight is OK.